Lamp base



FIG. 1 is a perspective view of the top, front and right side of a lamp base showing my new design, a conventional shade being shown in phantom lines and forming no part thereof;

FIG. 2 is a left side elevational view thereof on an enlarged scale;

FIG. 3 is a rear elevational view thereof on an enlarged scale;

FIG. 4 is a bottom plan view thereof on a reduced scale. 

The ornamental design for a lamp base, substantially as shown and described. 